Yeah we're limited by the reference AMD boards, no doubt with board with better power we'll see better OC

Anyway, It is said that due to the Threadripper being top binned die, average parts are actually able to hit 4Ghz at 1.32V or even way lower, compared to the average-ish Ryzen 7 that needs 1.4V+ to hit same 4Ghz target. So Best Ryzen 7 parts should be 'average' TR parts (which explains their slightly more aggressive 4.2Ghz XFR bin on TR).